1. Field of the Invention
The present invention relates to a snowmobile, in particular to a stopper mechanism for a snowmobile.
2. Description of the Related Art
A snowmobile is a vehicle for traveling on snow, in particular, the snowmobile runs on the surface of snow via a track belt, to which a driving force is transferred from an engine, and a pair of skis attached to the front of the vehicle body. The skis of the snowmobile can be rotated by a steering mechanism operated by a rider. The mechanism with which the steering rotates the skis is disclosed in e.g., U.S. Pat. Nos. 3,825,086; 4,826,184; 6,234,262; and 5,992,552.
The snowmobile often has a steering stopper attached to a link suspension so as to prevent the skis from rotating more than required. The steering stopper of the snowmobile usually uses two stoppers, a knuckle side stopper provided in a knuckle supporting the ski and a handlebar side stopper provided on the side of a handlebar.
The handlebar side stopper regulates excessive input from the handlebar caused by human operation and serves to prevent breakage of the steering system. On the other hand, the knuckle side stopper regulates a rotation direction during the handlebar operation and serves to prevent breakage of the steering system due to forces applied from the skis during full steering rotation of the vehicle. The steering stopper is designed such that the knuckle side stopper contacts a predetermined location around the knuckle before the handlebar side stopper operates and makes contact, in order to prevent breakage of the steering system due to forces applied from the skis.
However, the inventors discovered that there were some cases in which the knuckle side stopper was not exactly in contact with a predetermined location around the knuckle depending on a stroke (range of motion) of a front suspension. More specifically, in the case of a double wishbone type snowmobile including an upper arm and a lower arm, it often occurs that a rotation angle of the ski changes with the stroke of the front suspension and the knuckle side stopper is not in contact with the predetermined location around the knuckle, and thus the knuckle side stopper fails to function.
Even when the knuckle side stopper is not in contact with the predetermined location around the knuckle, the rotation of the ski can be controlled by the handlebar side stopper. However, in the situation where the knuckle side stopper is not in contact with the predetermined location around the knuckle, breakage of the steering system may not be prevented. In order to prevent breakage of the steering system, and also taking into consideration of the situation where the knuckle side stopper is not in contact with the predetermined location, it is necessary to increase the strength of a link system so as to withstand a reaction force applied from the skis during the vehicle rotation. However, increasing the strength of the link system might lead to an increase in the cost of the material and complexity of structure, and thereby lead to an increase in overall cost.